Ever since Jeremy Corbyn was elected Labour leader, Tory researchers have been scouring the archives for evidence of gaffes and outrages he may have committed during his lengthy and previously obscure career. Now, it seems, Owen Smith’s researchers have been scouring the archives too.

“I’ve never used bad language against anyone,” sniffed Mr Corbyn at tonight’s leadership hustings in Glasgow. Presumably he said this to remind Labour members that, a few days ago, Mr Smith had called him “a lunatic”.

Mr Smith retorted that he’d apologised for using such an insensitive word. But did the audience know, he went on, that in 1992 a Tory MP had been publicly derided as “a lunatic” by one J Corbyn?

In surprise, everyone looked at St Jeremy.

“I’d rather we got on to discussing politics,” he sniffed.

Mr Corbyn does a lot of sniffing.

Week by week, the Labour leadership hustings are growing bitterer. At the start of this one, each candidate was asked to guess what his opponent’s supporters saw in him. Their answers were brief, and dripped with faint praise.

Mr Corbyn noted that Mr Smith “has experience in the private sector”. Translation: he’s a neoliberal bourgeois capitalist corporate sell-out. Of Mr Corbyn, the best Mr Smith could say was that “He’s got convictions and he’s stuck with them, all this time later.” Translation: the silly old goat is stuck in the past.

The most bad-tempered exchanges were over Brexit. And it wasn’t just the candidates who were cross. Mr Smith was booed and heckled by a few members of the audience for saying he’d try to block the Government from triggering Article 50, and thus prevent Britain from leaving the EU.

Undeterred, Mr Smith then attacked Mr Corbyn for refusing to issue the same threat. Clearly, he snapped, Mr Corbyn was secretly “happy with the result” of the EU referendum. Mr Corbyn protested his innocence. Remarkably, and perhaps for the first time at an event attended by Labour members, Mr Corbyn received some jeers.

“People shouldn’t be jeering Jeremy,” said Mr Smith. “But I think Jeremy should have told the people jeering me to stop, too!” From generous to derisive in a single line.

Then Mr Smith started asking Mr Corbyn whether he’d secretly voted to leave the EU. Mr Corbyn neglected to answer. Gleefully Mr Smith asked him again. Again Mr Corbyn neglected to answer. Only after another round of badgering did Mr Corbyn acknowledge the question, hotly insisting that he’d voted Remain. It was deeply disappointing, he added, that Mr Smith should question his integrity in this manner. The only other people who’d doubted him, he sniffed, “were the Daily Mail.”

The Daily Mail. Heavens. Even worse than the private sector.

Mr Smith will probably feel he won that exchange. I’m not sure he should. After all: if he can get jeered for opposing Brexit in Scotland, which voted to stay, imagine how he’ll go down in England and Wales.